Sleeve for medical device assembly

ABSTRACT

The present disclosure describes a medical device assembly comprising an expandable medical device wrapped with an improved constraining sleeve. The sleeve in accordance with various embodiments of the present disclosure is thin walled and translucent, having reduced edge sharpness. The sleeve in accordance with the present disclosure exhibits resistance to ripping and delamination. Various embodiments of the present disclosure provide methods of making sheet material usable for constraining sleeves from flattened film tubes. Methods for making improved constraining sleeves and medical device assemblies that comprise an improved constraining sleeve are also disclosed herein.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.16/025,071, filed Jul. 2, 2018, now U.S. Pat. No. 10,675,388, grantedJun. 9, 2020, which a divisional of U.S. application Ser. No.14/066,454, filed Oct. 29, 2013, now U.S. Pat. No. 10,010,654, grantedJul. 3, 2018, which claims the benefit of Provisional Application No.61/720,330, filed Oct. 30, 2012, which are incorporated herein byreference in their entireties for all purposes.

FIELD

The present disclosure relates in general to medical device assembliesand more particularly to improved constraining members for use in thesame.

BACKGROUND

Medical devices are frequently used to treat the anatomy of patients.Examples of such devices include stents, grafts, stent-grafts, filters,valves, occluders, markers, mapping devices, therapeutic agent deliverydevices, prostheses, pumps, bandages, and the like. Such devices can beimplanted. Such devices can also be expandable and deliveredendoluminally. In the latter case, an expandable device, is constrainedby a constraining member, such as a sheath or a sleeve, toward a reduceddelivery profile suitable for endoluminal delivery on a catheter,introduced into the body at an insertion point, delivered endoluminallytoward a treatment site, and expanded at the treatment site.

Although many improvements have been made to medical device assembliesin general, constraining members, configured with sufficient strength toconstrain expandable devices, can reduce the flexibility and increasethe profile of devices due to the thickness of the materials used.Conversely, thinner walled constraining members can rip apart at stitchlines. Constraining members can burst when used to constrainself-expanding devices to very small delivery profiles.

Therefore, smaller profile medical device assemblies that can bereliably introduced and moved through body conduits such as thevasculature are desired. In particular, thinner and strongerconstraining members for use with expandable medical devices aredesired.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the disclosure and are incorporated in and constitute apart of this specification, illustrate embodiments of the disclosure,and together with the description serve to explain the principles of thedisclosure, wherein:

FIG. 1 illustrates a perspective view of an embodiment of an expandedmedical device in a collapsed configuration in accordance with thepresent disclosure;

FIG. 2 illustrates a perspective view of an embodiment of an expandablemedical device constrained in a collapsed configuration in accordancewith the present disclosure;

FIG. 3 illustrates a perspective view of an embodiment of a tubularcoaxial constraining sleeve in accordance with the present disclosure;

FIG. 4 illustrates a perspective view of an embodiment of a longitudinaltape wrapping process in accordance with the present disclosure;

FIG. 5 illustrates a perspective view of an embodiment of a partiallyformed film tube in accordance with the present disclosure;

FIG. 6 illustrates a perspective view of an embodiment of a helical tapewrapping process in accordance with the present disclosure;

FIG. 7a illustrates a perspective view of an embodiment of a film tubein accordance with the present disclosure;

FIG. 7b illustrates a perspective view of an embodiment of a flattenedfilm tube in accordance with the present disclosure;

FIG. 7c illustrates a cross sectional view of an embodiment of aflattened film tube in accordance with the present disclosure; and

FIG. 7d illustrates a perspective view of an embodiment of a tubularcoaxial sleeve in accordance with the present disclosure.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Persons skilled in the art will readily appreciate that various aspectsof the present disclosure can be realized by any number of methods andsystems configured to perform the intended functions. Stateddifferently, other methods and systems can be incorporated herein toperform the intended functions. It should also be noted that theaccompanying drawing figures referred to herein are not all drawn toscale, but can be exaggerated to illustrate various aspects of thepresent disclosure, and in that regard, the drawing figures should notbe construed as limiting.

With that said, and as will be described in more detail herein, variousembodiments of the present disclosure generally comprise a medicaldevice assembly further comprising an expandable medical devicecompacted toward a reduced outer peripheral dimension suitable forendoluminal delivery and covered with an improved constraining sleeve.An improved sleeve in accordance with various embodiments of the presentdisclosure is thin walled and translucent. Furthermore, variousembodiment of an improved sleeve exhibit reduced edge sharpness, highstrength and resistance to ripping.

Additionally, and as will be described in more detail herein, variousembodiments of the present disclosure also comprise methods ofmanufacturing improved constraining sleeves for use in medical deviceassemblies, methods of manufacturing sheet material suitable for use inconstraining sleeves, and methods of manufacturing medical deviceassemblies comprising improved constraining sleeves.

As used herein, “medical devices” can include, for example, stents,grafts, stent-grafts, filters, valves, occluders, markers, mappingdevices, therapeutic agent delivery devices, prostheses, pumps,bandages, and other endoluminal and implantable devices that areimplanted, acutely or chronically, in the vasculature (vessel) or otherbody lumen or cavity at a treatment region or site. Such medical devicescan comprise a flexible material that can provide a fluid-resistant orfluid-proof surface, such as a vessel bypass or blood occlusion.

As used herein, an “expandable implant” can include any medical devicedeliverable to the treatment site at a compacted delivery profile andcapable of dilation from the delivery profile, through a range ofintermediary outer peripheral dimensions, and toward a maximal,pre-determined functional outer peripheral dimension. Such expandabledevices can include, for example, stents, grafts, and stent-grafts.

As used herein, translucent means semitransparent. Light will passdiffusely or partially through translucent material.

In various embodiments, an expandable implant can comprise a collapsedconfiguration suitable for endoluminal delivery of the implant towardthe treatment area of the vasculature of a patient. Such an expandableimplant can be constrained toward a generally radially collapsedconfiguration and mounted onto a delivery device such as a catheter. Thedelivery profile or outer peripheral dimension of the expandable implantin the collapsed configuration is preferably small enough for theimplant to be delivered through the vasculature to the treatment area.In various embodiments, the outer peripheral dimension of the collapsedconfiguration is small enough to minimize the crossing profile of acatheter and reduce tissue damage to the patient. In the collapsedconfiguration, the expandable implant can be guided through thevasculature.

In various embodiments, an expandable implant can comprise a generallyradially expanded configuration suitable for implanting the device inthe treatment area of a patient's vasculature. In the expandedconfiguration, the outer peripheral dimension of an expandable implantcan approximate the vessel to be repaired. In other embodiments, theouter peripheral dimension of expandable implant in the expandedconfiguration can be slightly larger than the vessel to be treated toprovide a traction fit within the vessel.

In various embodiments, an expandable implant can comprise aself-expandable device, such as a self-expandable stent-graft. Suchdevices dilate from a generally radially collapsed configuration towarda generally radially expanded configuration when unconstrained. As usedherein, the term “constrain” can mean (i) to limit expansion, occurringeither through self-expansion or expansion assisted by a device, of anexpandable implant, or (ii) to cover or surround, but not otherwiserestrain, an expandable implant (e.g., for storage or biocompatibilityreasons and/or to provide protection to the expandable implant and/orthe vasculature).

In various embodiments, an expandable implant can comprise a device thatis expanded with the assistance of a secondary device such as, forexample, a balloon.

In various embodiments, an expandable implant can comprise astent-graft. Stent-grafts are designed to generally comprise one or morestent components that form a support structure or scaffold, with one ormore graft members displaced over and/or under the stent.

In various embodiments, the support structure can comprise, for example,a plurality of stent rings, cut tubes, wound wires (or ribbons) or flatpatterned sheets rolled into a tubular form. Stent rings can beoperatively coupled to one another with a wire. A wire used to couplestent rings can attach to the peak of a first stent ring and a valley ofa second stent ring. The stent ring can be arranged such that the peaksin valleys are in-phase (e.g., the peaks of the first stent ring share acommon centerline with the peaks of the second stent ring) or out ofphase (e.g., the peaks of the first stent ring share a common centerlinewith the valleys of the second stent ring).

Stent components for support structure can be formed from metallic,polymeric or natural materials, and can comprise conventional medicalgrade materials such as for example nylon, polyacrylamide,polycarbonate, polyethylene, polyformaldehyde, polymethylmethacrylate,polypropylene, polytetrafluoroethylene, polytrifluorochlorethylene,polyvinylchloride, polyurethane, elastomeric organosilicon polymers;metals such as iron alloys, stainless steels, cobalt-chromium alloys,nitinol, and the like; and biologically derived materials such as bovinearteries/veins, pericardium and collagen. Stent components can alsocomprise bioresorbable organic materials such as poly(amino acids),poly(anhydrides), poly(caprolactones), poly(lactic/glycolic acid)polymers, poly(hydroxybutyrates) and poly(orthoesters). Any expandablestent component configuration that can be delivered to a treatment siteis in accordance with the present disclosure.

In various embodiments, graft materials in stent-grafts can include, forexample, expanded polytetrafluoroethylene (ePTFE), polyester,polyurethane, fluoropolymers, such as perfluoroelastomers and the like,polytetrafluoroethylene, silicones, urethanes, ultra high molecularweight polyethylene, aramid fibers, and combinations thereof. Otherembodiments for a graft member material can include high strengthpolymer fibers such as ultra-high molecular weight polyethylene fibers(e.g., Spectra®, Dyneema Purity®, etc.) or aramid fibers (e.g.,Technora®, etc.). The graft member can include a bioactive agent. In oneembodiment, an ePTFE graft includes a carbon component along a bloodcontacting surface thereof. Any graft member that can be delivered in apatient to a treatment site is in accordance with the presentdisclosure.

In various embodiments, a stent component and/or graft member cancomprise a therapeutic coating. In these embodiments, the interior orexterior of the stent component and/or graft member can be coated with,for example, a CD34 antigen. Additionally, any number of drugs ortherapeutic agents can be used to coat the graft member, including, forexample heparin, sirolimus, paclitaxel, everolimus, ABT-578,mycophenolic acid, tacrolimus, estradiol, oxygen free radical scavenger,biolimus A9, anti-CD34 antibodies, PDGF receptor blockers, MMP-1receptor blockers, VEGF, G-CSF, HMG-CoA reductase inhibitors,stimulators of iNOS and eNOS, ACE inhibitors, ARBs, doxycycline, andthalidomide, among others.

In various embodiments, an expandable implant such as a stent-graft canbe constrained by a constraining member or a “sleeve,” whichperipherally surrounds the expandable implant. In various embodiments, asleeve peripherally surrounds an expandable implant and constrains ittoward a collapsed configuration in which the outer peripheral dimensionis less than the outer peripheral dimension of the unconstrainedimplant. For example, a sleeve can constrain an expandable implanttoward a collapsed configuration or outer peripheral dimension suitablefor endoluminal delivery toward a treatment site within the vasculature.

In various embodiments, sleeves can be tubular and serve to constrain anexpandable implant such as a stent-graft. In such configurations,sleeves are formed from at least one sheet material wrapped or foldedabout the expandable implant. While the illustrative embodiments hereinare described as comprising one or more tubular sleeves, sleeves of anynon-tubular shape that correspond to an underlying expandable implant orthat are otherwise appropriately shaped for a given application are alsowithin the scope of the present disclosure.

In various embodiments, sleeves can comprise materials such as AmorphousCommodity Thermoplastics that include Polymethyl Methacrylate (PMMA orAcrylic), Polystyrene (PS), Acrylonitrile Butadiene Styrene (ABS),Polyvinyl Chloride (PVC), Modified Polyethylene Terephthalate Glycol(PETG), Cellulose Acetate Butyrate (CAB); Semi-Crystalline CommodityPlastics that include Polyethylene (PE), High Density Polyethylene(HDPE), Low Density Polyethylene (LDPE or LLDPE), Polypropylene (PP),Polymethylpentene (PMP); Amorphous Engineering Thermoplastics thatinclude Polycarbonate (PC), Polyphenylene Oxide (PPO), ModifiedPolyphenylene Oxide (Mod PPO), Polyphenylene Ether (PPE), ModifiedPolyphenylene Ether (Mod PPE),Thermoplastic Polyurethane (TPU);Semi-Crystalline Engineering Thermoplastics that include Polyamide (PAor Nylon), Polyoxymethylene (POM or Acetal), Polyethylene Terephthalate(PET, Thermoplastic Polyester), Polybutylene Terephthalate (PBT,Thermoplastic Polyester), Ultra High Molecular Weight Polyethylene(UHMW-PE); High Performance Thermoplastics that include Polyimide (PI,Imidized Plastic), Polyamide Imide (PAI, Imidized Plastic),Polybenzimidazole (PBI, Imidized Plastic); Amorphous High PerformanceThermoplastics that include Polysulfone (PSU), Polyetherimide (PEI),Polyether Sulfone (PES), Polyaryl Sulfone (PAS); Semi-Crystalline HighPerformance Thermoplastics that include Polyphenylene Sulfide (PPS),Polyetheretherketone (PEEK); and Semi-Crystalline High PerformanceThermoplastics, Fluoropolymers that include Fluorinated EthylenePropylene (FEP), Ethylene Chlorotrifluroethylene (ECTFE), Ethylene,Ethylene Tetrafluoroethylene (ETFE), Polychlortrifluoroethylene (PCTFE),Polytetrafluoroethylene (PTFE), Polyvinylidene Fluoride (PVDF),Perfluoroalkoxy (PFA).

In various embodiments, tape can comprise any of the above-listedmaterials or combinations thereof, and in various embodiments, such tapecan be used to build layers that are laminated together into sheetmaterial for sleeves. Examples of laminated materials, such as PTFE filmlaminated to another substrate, can be found in U.S. Pat. No. 7,521,010to Kennedy et al., the content of which is incorporated herein byreference in its entirety.

In various embodiments, sleeves are formed by wrapping sheet materialsuch that two opposing and/or parallel edges of the sheet aresubstantially aligned. The alignment may or may not be parallel to orcoaxial with the catheter shaft of a catheter assembly. In variousembodiments, the edges of the sheet material(s) do not contact eachother.

In various embodiments, the edges of the sheet material(s) contact eachother and are coupled together with an elongated coupling member, asdescribed below. In various other embodiments, the edges of the sheetmaterial(s) are aligned so that the edges of the same side of the sheetor sheets (e.g., the front or back of the sheet) are in contact witheach other. In still other embodiments, the edges of opposite sides ofthe sheet material(s) are in contact with each other, such that theedges overlap each other, such that a portion of one side of the sheetis in contact with a portion of the other side. Said another way, thefront of the sheet can overlap the rear of the sheet, or vice versa.

In various embodiments, the sheet material includes a row of openingsperforated by any method along each opposing edge, which are configuredto accommodate the elongated coupling member such that the elongatedcoupling member can secure the sheet material into a tubular shapearound the expandable device. In various embodiments of an improvedsleeve, reinforcement fibers, or other similar materials or compounds,can be provided to prevent the elongated coupling member from rippingthrough the sleeve proximate to the openings.

For example, in various embodiments, sleeves used to constrainexpandable implants further comprise any number of reinforcing fibers.In such embodiments, fibers are laid onto, or embedded into, sheetmaterial used to form the sleeve. Reinforcing fibers can be comprised ofany suitable flexible strand possessing high-strength and minimalelongation as known in the art. In various embodiments, a high-strengthfiber can have a tensile strength ranging from about 0.5 Gpa to about2.5 Gpa or higher, and can have an elongation to break of less thanabout 5%. Exemplary reinforcing fibers include, but are not limited to,polyethylene fiber, polyimide fiber, ePTFE fiber such as KORETEK®,polyether fiber such as polyethylene terephthalate (DACRON® or MYLAR®),polyacrylamide fiber such as KEVLAR®, liquid crystal polymer fiber, andmetal fiber such as nitinol, stainless steel, or gold, and combinationsthereof.

In various embodiments, the reinforcing fiber or fibers within aconstraining sleeve can have varied diameters and/or cross-sectionalprofiles. For example, the fibers can have a circular cross-section witha diameter ranging from about 0.0001 mm to about 1 mm. In variousembodiments, the fibers can have a circular cross section of about 0.01mm to about 0.1 mm. In various embodiments, the fibers can have acircular cross-section of about 0.03 mm to about 0.05 mm. In addition,reinforcing fibers can have a non-circular cross-section, such as, forexample, a triangle, rectangle, square or other geometric shape.Moreover, the geometry of the one or more reinforcing fibers present ina constraining sleeve can be the same or varied. For example,circumferentially oriented fibers can have a substantially flatcross-section, whereas longitudinally oriented fibers can have asubstantially circular cross-section.

In various embodiments, sleeves used to constrain expandable implantscan further comprise radiopaque or echogenic markers. In suchconfigurations, radiopaque markers can be located at the edges ofsleeves, in the region where a coupling member is stitched through theseries of openings. Radiopaque markers can assist in the positioning andorientation of the expandable implant within a vasculature, for example,by increasing the visibility through imaging of the location andorientation of elements such as sleeves, coupling members, sidebranches, fenestrations, fenestratable areas, cuffs, anchors, and thelike.

As used herein, “deployment” refers to the actuation of the medicaldevice at or near a treatment site, such as for example, the removal ofa sleeve on a self-expandable implant to allow the implant to expand.Upon such deployment, the sleeve or sleeves can be removed to allow theexpandable implant to expand toward a functional or deployed outerperipheral dimension and achieve a desired therapeutic outcome. In someembodiments, the sleeve or sleeves can remain implanted while notinterfering with the expandable implant. In other embodiments, thesleeve or sleeves can be removed.

In various embodiments, deployment of a self-expandable stent-graft cancomprise pulling out a coupling member that was used in securing thesleeve over the stent-graft, maintaining it in a collapsedconfiguration. This process of removing the coupling member from thesleeve is also referred to herein as “disengagement.” Examples ofconstraining members and coupling members for releasably maintainingexpandable devices in a collapsed state for endoluminal delivery can befound in U.S. Pat. No. 6,352,561 to Leopold et al., the content of whichis incorporated herein by reference in its entirety.

In various embodiments, when the expandable implant, such as astent-graft, is in position within the vasculature, the coupling membercan be disengaged from the sleeve from outside of the body of thepatient, which allows the sleeve to open and the expandable implant toexpand. As discussed above, the expandable implant can beself-expanding, or the implant can be expanded by a second device, suchas a balloon. The coupling member can be disengaged from the sleeve by amechanical arrangement operated from outside of the body of the patient.For example, the coupling member can be disengaged by applyingsufficient tension to the member. In another example, a dial, rotationalelement, or any suitable actuation member can be operatively connectedto the coupling member outside of the body such that rotation oractuation of the dial or rotational element or actuation member providessufficient tension to disengage the coupling member.

In various embodiments, a sleeve and a method of making the same isdisclosed herein, which can result in constraining sleeves that are thinand translucent, have reduced edge sharpness, and yet maintain highburst strength and resistance to ripping or stitch line pull out.

The above being noted, with reference now to FIG. 1, a medical device100 in accordance with the present disclosure is illustrated. Medicaldevice 100 comprises a stent 102 and a graft member 104. In variousembodiments, graft member 104 is affixed to the outside surface of stent102 such that once deployed, graft member 104 is placed into contactwith a vessel wall. In other embodiments, graft member 104 is affixed tothe inside surface of stent 102.

Referring now to FIG. 2, an embodiment of a medical device assembly 220in accordance with the present disclosure comprises an expandable device200, such as a stent graft. The expandable device 200 is compacted orconstrained by a constraining member or sleeve 210 toward a reducedouter peripheral dimension suitable for endoluminal delivery of thedevice to a treatment site. In various embodiments, constraining memberssuch as constraining sleeve 210 can comprise materials similar to thoseused to form a graft member. As will be discussed below, flattened thinwall ePTFE film tubes provide suitable starting material for sleeve 210.The constraining sleeve 210, when made in accordance with the presentdisclosure, can be thin walled. Such a thin walled constraining sleeve210 may add only minimally to the total delivery profile of the device,yet still be strong enough to securely constrain an expandable devicetoward a reduced outer peripheral dimension.

In the embodiment illustrated in FIG. 2, the sleeve 210 includesgenerally opposite and/or parallel edges or portions 212 each with aplurality of openings 208 such as eyelets. The openings 208 are arrangedin rows to form stitch lines 214 extending along the opposite portions212 of the sleeve 210. The sleeve 210 extends around the device 200,with the opposing portions releasably secured together to define areleasable seam 216 that runs axially along the length of the sleeve210. In this case, a flat sheet material can be wrappedcircumferentially around the device for closure to form such a seam.

In various embodiments, the releasable seam 216 can be held together byan elongated coupling member 206 extending through or woven through theopenings 208. The threading or weave can comprise any variation ofstitching, such as for example a chain stitch comprising individual slipknots or loops 204 that are interconnected. In various embodiments, thecoupling member 206 can comprise a woven fiber. In other embodiments,the coupling member 206 can comprise a monofilament fiber. Any type ofstring, cord, thread, fiber, or wire capable of maintaining a sleeve ina tubular shape is within the scope of the present disclosure. Thecoupling member 206 can comprise ePTFE fiber such as KORETEK®, suturesof polyethers such as polyethylene terephthalate (DACRON® or MYLAR®) orpolyacrylamides such as KEVLAR®. The coupling member 206 canalternatively comprise a metal wire made from nitinol, stainless steel,or gold. In various embodiments, the coupling member 206 can extend longenough to form a remote pull line or can be coupled to a separate pullline of the same or different material.

In various embodiments, when the expandable device 200 is in position ator near the treatment site of the patient, the elongated coupling memberor members 206 can be disengaged from the sleeve or sleeves 210 fromoutside of the body of the patient, which allows the sleeve(s) to openand the expandable device 200 to expand.

In various embodiments, the coupling member 206 can extend through acatheter shaft and be accessed by a clinician through proximalconnectors. Tensioning, actuation and displacement of the couplingmember 206 from the openings 208 allows the sleeve 210 to open along thereleasable seam 216 and for the device 200 to expand from a reducedouter peripheral dimension suitable for endoluminal delivery to atreatment site toward a larger outer peripheral dimension duringdeployment at or near the treatment site.

Referring now to FIG. 3, a perspective view of an embodiment of aconstraining sleeve 310 in accordance with the present disclosure isillustrated. Sleeve 310 can be substantially tubular to fit generallycoaxially over an expandable device in a medical device assembly. Thetubular shape can be obtained by wrapping sheet material 330 around thedevice and bringing opposing ends 312 into close proximity for coupling.The wrapping of sheet material 330 to form the tubular sleeve 310 can beconcomitant with the compression of an expandable device to a compact orreduced outer peripheral dimension, or it can be at any other timeduring the process of assembling a medical device assembly. The tubularsleeve 310 can include rows of openings 308. The openings 308 can beconfigured through the sleeve 310 at any time during the manufacturingof the sheet material 330 or at any other time during the process ofassembling the medical device assembly.

Still referring to FIG. 3, a sleeve 310 in accordance with the presentdisclosure includes at least one reinforcing fiber 318 substantiallyembedded within sheet material 330 as illustrated. Such embedding of thefiber(s) 318 can be accomplished by thermal, ultrasonic, ultraviolet, orsolvent bonding of layers of sheet material with the fiber(s) placed on,or sandwiched between, layers of sheet material. Such bonding results ina flow of sheet material over and around the one or more reinforcingfibers, thereby encasing the fiber(s). The one or more reinforcingfibers 318 extend along at least one of the opposing ends 312 of theshaped sleeve 310, as in the embodiment illustrated. As discussed above,in various embodiments, the tubular constraining sleeve 310 includes tworows of openings 308 positioned along opposing ends 312 of the sheetmaterial that can be used for securing the sleeve 310 with an elongatedcoupling member. A reinforcing fiber 318 is disposed within the sheetmaterial 330 along each of the two opposing ends 312 such that the twofibers 318 strengthen the releasable seam 316 once the opposing ends 312are coupled together by an elongated coupling member woven through theopenings 308. Disposed longitudinally between the row of openings 308and the edge 312, each reinforcing fiber 318 acts as a rip-stop,preventing the elongated coupling member from tearing through the sheetmaterial 330 proximate to the openings 308.

With continued reference to FIG. 3, a sleeve 310 constructed inaccordance with the present disclosure can have minimal edge sharpnessalong both opposing edges 312. Additionally, sleeve 310 can have a finalwall thickness x of less than about 0.12 mm. In various embodiments,thickness x is less than about 0.10 mm. In various embodiments,thickness x ranges between about 0.08 and about 0.10 mm. The final wallthickness x of the sheet material 330 used for the sleeve 310 can arisefrom any number of precursor layers of sheet material, such as ePTFE,which can be bonded to create the finished sheet material 330. Withbonding of precursor layers, any separate layers that may havecontributed to the finished sheet material 330 may or may not bediscernible on either end of the sleeve 310 or in any cross-sectionalcut made through the sleeve 310.

In various embodiments, sleeve 310 in FIG. 3 is translucent, allowing alight transmission of 80% or greater, or 90% or greater, or 95% orgreater over a wide spectrum of incident wavelengths. A translucentsleeve allows a view of the expandable device through the sleeve, whichis particularly advantageous during assembly of the sleeve and theconstrained device.

In various embodiments and with reference to FIG. 3, sleeve 310 exhibitshigh burst strength and a high resistance to ripping of sheet material330 proximate to the openings 308. Burst strength and tensile strengthmeasurements are detailed below.

Referring now to FIG. 4, an embodiment of a method of manufacturing aconstraining sleeve in accordance with the present disclosure isillustrated. Spools 446 and 448 are used to supply tape 422 and 424 togenerally opposite sides of a longitudinally presented rod or mandrel440. In various embodiments, tape for this process can comprise anycombination of materials used for tape as discussed above, such as ePTFEoptionally coated at least partially on one or both sides with anadhesive material such as fluorinated ethylene propylene (FEP). Methodsof making ePTFE sheets or tape can be found in U.S. Pat. No. 5,792,525to Fuhr et al., the content of which is incorporated herein by referencein its entirety. The mandrel 440 can be heated intermittently orcontinuously to bond together the longitudinal wrappings of tape into atubular film layer 426. The mandrel 440 can be heated utilizing anysuitable means, such as by conductive or inductive heating. An inductionheater, for example as produced by Ambrell®, can be used to heat themandrel to at least about 300° C. when the tape has begun to wrapcorrectly.

As illustrated in FIG. 4, generally longitudinal placement orapplication of tape 422 and 424 can be assisted by guides 441 and 443that slide along the mandrel 440 in an automated process. Guides 441 and443 can be used to push the tape 422 and 424 firmly toward the mandrel440 and assist in bonding overlapped portions of tape into longitudinalseams 444. The guides can also be heated for this purpose. The finishedtubular layer of film 426 thus formed can comprise any number ofoverlapping tape portions. When two longitudinally overlapping tapes areused, the sum of the widths of tape 422 and tape 424 are greater thanthe circumference of the mandrel 440 such that the two opposing runs oftape will overlap on the mandrel to form longitudinal seams 444. Anynumber of first layers of film can be produced in this manner, usingtape fed in from any direction and from any number of spools. Althoughthe wrapping of tape is illustrated in FIG. 4 as longitudinal inorientation, the first layer(s) of film 426 can be made by anycombination of longitudinal or cigarette wrapping, radial or helicalwinding. In various embodiments, the orientation of the wrapping of thetape and hence, the longitudinal or machine direction, can be chosen togive one or more different characteristics to the film layer producedfrom the wrappings. For example, the burst strength of a film layer canbe improved by increasing the angle of wrapping relative to thelongitudinal axis of the mandrel. The process of wrapping tape on amandrel to produce film tubes can be an entirely manual, partiallyautomated, or fully automated process, as deemed appropriate.

Referring now to FIG. 5, at least one reinforcing fiber 518 ispositioned against the at least one layer of film 526 that was producedby wrapping tape on the mandrel 540. The one or more fibers 518 can bepositioned on the mandrel 540 in any direction as needed. In theembodiment illustrated, two lengths of reinforcing fiber 518 arepositioned longitudinally down the cylindrical mandrel 540 generallyparallel to both the overlapped tape seam 544 and to each other. Whentwo fibers 518 are utilized in this manner, they are disposed onopposite sides of the mandrel as close as possible to a 180° separationfrom one another along the length of the mandrel. As discussed below,once the one or more reinforcing fibers 518 are positioned against thefirst layer(s) of film 526, additional windings of tape can then bewound in order to sandwich these fibers between film layers and build afilm tube.

Referring now to FIG. 6, tape 622 is applied around the mandrel 640 toform any number of additional layers to the film tube. In variousembodiments, tape 622 can be formed from ePTFE, which can be coated atleast partially on at least one side with an adhesive material such asfluorinated ethylene propylene (FEP) for bonding of tape 622 to thefirst film layer(s) 626 and fibers 618. Although helical winding isillustrated, windings 642 can comprise any combination of longitudinal,helical or radial winding, with any degree of overlap in the windings.For example, it can be desirable to wrap a number of helical windings ata particular pitch angle and overlap, and then add radial windings tobolster the radial strength of the finished film tube. As illustrated,additional windings 642 of tape 622 sandwich the one or more fibers 618between first film layer(s) 626 and the additional windings 642. Forcreating additional layers of film, tape 622 can be fed to the mandrel640 from one or more spools 646 appropriately positioned for the desiredtape orientation. The mandrel 640 can be heated, intermittently orcontinuously, at any time during or after the application tape 622 overthe fibers 618. Heating will bond the windings 642 into new layers offilm that will bond together with the first film layer(s) 626 to form asingle laminate that resists delamination. In the resulting laminate,the reinforcing fibers 618 will be embedded within the film composite.The completed, bonded and reinforced film tube can then be removed fromthe mandrel.

Referring now to FIG. 7a , an embodiment of a completed film tube 728 inaccordance with the present disclosure is illustrated. In thisembodiment, film tube 728 comprises two longitudinally orientedreinforcing fibers 718 positioned approximately opposite one anotherdown the length of the tubular structure, sandwiched between bonded filmlayer(s) 726 and layer(s) 734 and embedded therein. Opposing directionalarrows “a” show the direction of force used to flatten the film tube 728into a flattened film tube usable as a precursor to a tubularconstraining sleeve, (FIG. 7b ).

Referring now to FIG. 7b , an embodiment of a flattened film tube 730 inaccordance with the present disclosure is illustrated. The film tubeprior to flattening (728 in FIG. 7a ) can be flattened when it emergesin a heated condition from the mandrel such that the film tube wallsbond together when the tube is flattened. Alternatively, the tube can beflattened and bonded in a subsequent and separate operation using anynecessary degree of heat and pressure to flatten the film tube andinternally bond the opposing walls of the tube together. When the filmtube (728 in FIG. 7a ) is properly flattened, the embedded parallelfibers 718 will end up disposed along opposite edges of sheet material750 without any appreciable salvage hanging beyond substantiallyparallel boundaries marked by the reinforcing fibers 718. In variousembodiments, a resulting flattened tube 730 and final sheel material 750can be generally translucent and have a thickness y of less than about0.12 mm. In still other embodiments, thickness y is less than about 0.10mm. In yet other embodiments, thickness y is from about 0.08 to about0.10 mm.

Referring now to FIG. 7c , a cross-section of an embodiment of aflattened tube 730 in accordance with the present disclosure isillustrated. The parallel reinforcing fibers 718 are left sandwiched andbonded between the outer 734 and inner 726 film layers of the sheetmaterial 750 as illustrated. The sandwiching of the fibers 718 resultedfrom winding at least one first layer of tape on the mandrel; layingdown the reinforcing fibers along the mandrel over the at least onefirst layer of tape; winding additional layers of tape wound onto themandrel over the reinforcing fibers and the at least one first layer oftape thereby sandwiching the fibers 718 between film layers on themandrel; and bonding embedded the fibers therein. The ability to discernlayers at the ends of the flattened tube or in a cross-section cutthrough the flattened tube (such as FIG. 7c ) generally depends on thedegree of bonding of the layers. Thickness z can also depend on anylater processing of the flattened film tube 730, such as further heat orsolvent bonding.

Still referring to FIG. 7c , excess film material 756 can extend to alength Ion either or both of the opposing ends 712 of the sheet material750 beyond the boundaries of the reinforcing fibers 718. In variousembodiments, length Ion either opposing edge 712 is no longer than about0.5 mm. The flattened film tube 730 thus formed will have little to nosharpness discernible along either opposing edge 712, and each edge 712will appear rounded with the fiber 718 being the axial core of eachrounded edge.

Referring now to FIG. 7d , an embodiment of a tubular sleeve 710 inaccordance with the present disclosure can be formed from the flattenedand bonded tube 730 by bringing the end portions 712 of the flattenedtube 730 into close proximity while shaping the flattened tube 730 intoa tubular configuration. The shaping can be facilitated by use of acylindrical substrate such as a rod or mandrel, or alternatively theflattened tube 730 can be circumferentially wrapped around an expandabledevice that is compacted toward a reduced or compacted outer peripheraldimension suitable for endoluminal delivery.

An embodiment of an improved constraining sleeve and methods of testingthe same in accordance with the present disclosure is described inconjunction with the following examples.

EXAMPLE 1

A constraining sleeve, in accordance with various embodiments, wasfabricated by the following process:

1) A steel mandrel was supplied having a diameter of about 12.4 mm(0.49″) and a length of about 30 cm (11.8″).

2) Four strips of film were then placed onto the mandrel, orientedlongitudinally along the length of the mandrel. The film had a width ofabout 22.2 mm (0.875″), a length of about 30 cm (11.8″). The individualfilm strips were oriented about 90° to each other with an edge to edgeoverlap of about 2.8 mm (0.11″). The film was comprised of non-porousePTFE provided with an adhesive coating (applied to one side of thefilm) of thermoplastic fluorinated ethylene propylene (FEP). The FEP wasoriented out and opposite of the mandrel surface. ePTFE is well known inthe medical device arts; it is generally made as described by U.S. Pat.Nos. 3,953,566 and 4,187,390 to Gore. The particular tape describedherein was slit from a substantially non-porous ePTFE/FEP film having athickness of about 0.0064 mm, an isopropyl bubble point of greater thanabout 0.6 MPa, a Gurley No. (permeability) of greater than 60 (minute/1square inch/100 cc); (or 60 (minute/6.45 square cm/100 cc)), a densityof 2.15 g/cc and a tensile strength of about 309 MPa in the longitudinallength direction (i.e., the strongest direction). The film ends werethen secured to the mandrel by an ePTFE suture.

3) A rip stop fiber was formed using the film described in Step 2).About 60 cm (23.6″) of the film was twisted into a fiber. The twistedfiber was then heat treated in an air convection oven at about 320° C.for about 5 minutes to reflow the FEP.

4) Two 30 cm (11.8″) long rip stop fibers from Step 3) were then placedlongitudinally along the mandrel/film strips from Step 2). The rip stopfibers were orientated about 180° from each other. The rip stop fiberends were then secured to the mandrel by an ePTFE suture.

5) A first layer of film was then helically wrapped onto themandrel/longitudinal film layers and the rip stop fibers. The film (asdescribed in Step 2) had a width of about 25.4 mm (1.0″) and was wrappedat an angle of about 33°. The film edges overlapped by about 4.2 mm(0.16″). The first helical film layer was applied in a single, left toright pass. The FEP was oriented out and opposite of the mandrelsurface. The film ends were then secured to the mandrel by an ePTFEsuture.

6) A second layer of film was then helically wrapped onto the firsthelically wrapped film in a single right to left pass. The secondhelical film was wrapped at an angle of about 12°. The film edgesoverlapped by about 0.44 mm (0.017″). The FEP was oriented in towardsthe mandrel surface. The film ends were then secured to the mandrel byan ePTFE suture.

7) The mandrel/film layers and rip stop fibers were then heat treated inan air convection oven at about 320° C. for about 10 minutes to reflowthe FEP and bond the assembly together.

The resulting tube, as illustrated in FIG. 7a , can be flattened andformed into a sleeve, as previously described in connection with FIGS.7b -7 d.

EXAMPLE 2

It should be appreciated that the mechanical properties of sleeves canbe evaluated using commonly known methods such as tensile tests,thickness measurements, density measurements, burst measurements,optical evaluations, and the like. A tensile test can quantify theresistance to ripping at edges of a sleeve, which is another measure ofsleeve strength. The following test methods can, for example, be used toevaluate the sleeve.

Thickness

The thickness of the sleeve was measured using a Starrett snap gauge.

Translucency

The translucency of a sleeve can be measured using a spectrophotometerthat records the percent light transmission (% T) through a sleeveacross the visible light spectrum.

Tensile Strength

Tensile strength was measured using an Instron® Model 4501 vertical pulltester, (Instron, Norwood, Mass.), with the clamping jaws of the testerinterlocked into a modified set of upper and lower clamps used to gripthe sleeve on each of the opposing edges. The modified clamps includetwo parallel rows of 24 tapered needle pins spaced 2.1 mm apart, eachpin having an end diameter of about 0.53 mm and a height of about 0.18mm. The rows of needle pins pierce and hold each opposing edge of thesleeve. The upper set of clamps aid in piercing the sleeve and toprevent the pins from bending during the test. The sleeve is positionedin the set of clamps with the reinforcing fibers of the sleeve behindthe rows of pins, such that the tester pulls against the reinforcingfibers embedded in the opposing edges of the sleeve. In this way, thedegree to which the reinforcing fibers act as rip-stops can beevaluated. A 500 kg load cell is used and the sleeve is tensioned at arate of 20 mm/min until the sleeve rips. The force to failure isreported in kg of force.

Burst Strength

Burst strength was measured by wrapping a sleeve to be tested around aninflatable bladder and securing the seam of the sleeve with an elongatedcoupling member. The bladder is then inflated until the sleeve bursts.The test can be conducted up to a practical limit of about 400 psi.

A translucent sleeve was made in accordance with the flattened film tubemethod set out in FIGS. 4 through 7 d and discussed above, incorporatingtwo lengths of 0.24 mm diameter reinforcing fiber in the process. Onceflattened, the flattened film tube measured 0.09 mm in thickness andabout 19 mm in width.

The force to failure for the sleeve was about 70 kg when tested asdetailed above.

The sleeve also exhibited a burst strength that exceeded 400 psi (thelimit of the test method). Based on this resistance to bursting, it isevident that the sleeve in accordance with the present disclosure isstrong in spite of being thin walled.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present disclosurewithout departing from the spirit or scope of the disclosure. Thus, itis intended that the present disclosure cover the modifications andvariations of this disclosure provided they come within the scope of theappended claims and their equivalents.

Likewise, numerous characteristics and advantages have been set forth inthe preceding description, including various alternatives together withdetails of the structure and function of the devices and/or methods. Thedisclosure is intended as illustrative only and as such is not intendedto be exhaustive. It will be evident to those skilled in the art thatvarious modifications can be made, especially in matters of structure,materials, elements, components, shape, size and arrangement of partsincluding combinations within the principles of the disclosure, to thefull extent indicated by the broad, general meaning of the terms inwhich the appended claims are expressed. To the extent that thesevarious modifications do not depart from the spirit and scope of theappended claims, they are intended to be encompassed therein.

What is claimed is:
 1. A biocompatible sheet material comprising: alaminate of at least four bonded layers of expandedpolytetrafluoroethylene film; and at least one reinforcing fiberembedded between any of the bonded layers, wherein the sheet material isfrom about 0.08 mm to about 0.10 mm thick, having a burst strength of400 psi or greater.
 2. The biocompatible sheet material of claim 1,wherein the biocompatible sheet material includes at least tworeinforcing fibers, the biocompatible sheet material includes twogenerally parallel and opposing edges, and wherein a first one of thereinforcing fibers is disposed along a first one of the opposing edgesand a second one of the reinforcing fibers is disposed along a secondone of the opposing edges.
 3. The biocompatible sheet material of claim1, wherein the at least one reinforcing fiber is embedded between thebonded layers such that at least one of the four bonded layers includesa portion that extends beyond a boundary defined by the at least onereinforcing fiber.
 4. The biocompatible sheet material of claim 1,wherein the biocompatible sheet material has a visible lighttransmission of about 80% or greater.
 5. The biocompatible sheetmaterial of claim 1, wherein the biocompatible sheet material has avisible light transmission of about 90% or greater.
 6. The biocompatiblesheet material of claim 1, wherein the biocompatible sheet material hasa visible light transmission of about 95% or greater.
 7. Thebiocompatible sheet material of claim 1, wherein the biocompatible sheetmaterial includes two generally parallel and opposing edges having aplurality of openings.
 8. The biocompatible sheet material of claim 7,wherein the plurality of openings are arranged in rows forming stitchlines extending along each of the two generally parallel and opposingedges.
 9. The biocompatible material of claim 8, wherein the twogenerally parallel and opposing edges are releasably secured to define areleasable seam.
 10. A method of manufacturing a medical device assemblycomprising: wrapping a biocompatible sheet material circumferentiallyaround an expandable medical device compressed into an outer peripheraldimension suitable for introduction into a body conduit, thebiocompatible sheet material including a laminate of at least fourbonded layers of expanded polytetrafluoroethylene film, and at least onereinforcing fiber embedded between any of the bonded layers, wherein thesheet material is from about 0.08 mm to about 0.10 mm thick, having aburst strength of 400 psi or greater; piercing two rows of openingsalong each of the opposing edges; and coupling the opposing edges bystitching an elongated coupling member through the openings to produce areleasable seam.
 11. The method of claim 10, further comprisingcompressing the expandable medical device prior to coupling the opposingedges of the biocompatible sheet material.
 12. The method of claim 10,further comprising compressing the expandable medical device concomitantwith coupling the opposing edges of the biocompatible sheet material.13. The method of claim 10, wherein the at least one reinforcing fiberis disposed along at least one of the opposing edges and embedded withinthe sheet.
 14. The method of claim 1, wherein the biocompatible sheetmaterial includes at least two reinforcing fibers longitudinally suchthat a first one of the reinforcing fibers is disposed along a first oneof the opposing edges and embedded between layers of the biocompatiblesheet material and such that a second one of the reinforcing fibers isdisposed along a second one of the opposing edges and embedded betweenthe layers of the biocompatible sheet material.
 15. The method of claim1, wherein the biocompatible sheet material has a visible lighttransmission of about 80% or greater.
 16. The method of claim 1, whereinthe biocompatible sheet material has a visible light transmission ofabout 90% or greater.
 17. The method of claim 1, wherein thebiocompatible sheet material has a visible light transmission of about95% or greater.
 18. A method of manufacturing a biocompatible sheetmaterial comprising: placing at least four layers of film onto amandrel; placing a fiber formed from a second material on the mandrel;bonding the at least four layers of film, the fiber, and a third film toform a tube, including compressing the tube while the tube is in aheated condition to form a biocompatible sheet material from about 0.08mm to about 0.10 mm thick having a burst strength of 400 psi or greater.19. The method of claim 18, further comprising helically wrapping thethird film on the mandrel in a single pass.
 20. The method of claim 19,further comprising helically wrapping a fourth film in a single passover the third film.